1) Field of the Invention
The field of this invention relates to an improved performance spark plug for an internal combustion engine which not only achieves increased operating efficiency but operates in a manner that substantially eliminates the fouling of the spark plug.
2) Description of Prior Art
Spark plugs are used in internal combustion engines (except diesel engines) to provide high voltage sparks that ignite the fuel/air mixture within the combustion chambers of the engine. When the engine is running, a pulse of electrical energy, at very high voltage, is delivered to the terminal of the spark plug at the correct moment by means of a spark generating device. The spark is caused to jump the gap between the center electrode and the ground electrode of the spark plug. The spark provides the energy needed to ignite the compressed fuel/air mixture in the cylinder of the engine.
It has been found that, for optimum performance, that the temperature of the core nose at the firing end of the spark plug should not drop below 400.degree. centigrade nor exceed about 850.degree. centigrade. Below 400.degree. centigrade, deposits of carbon and oil are likely to accumulate. Carbon being electrically conductive, can provide a short circuit path for the high voltage pulse and so weaken or eliminate the spark. Therefore, a fouled spark plug causes incomplete burning of the fuel/air mixture and possibly may cause non-ignition of the fuel/air mixture.
A lot of effort has been expended in the past to design spark plugs in conjunction with four-cycle engines. Within a two-cycle engine, the propensity for a fouled spark plug is greater as generally a two-cycle engine runs colder.
The conventional type of spark plug utilizes a strip-type of ground electrode which overlies the tip of the center electrode. This strip assumes a slight gap from the center electrode across which the spark is to occur. This type of spark plug has but one spark presentation, that being that the spark occurs at approximately the same location each time the spark plug is operated. Any accumulations of oil or carbon, not located directly in the path of the firing of the spark plug, will remain adhered to the surface of the spark plug and will accumulate and result in inefficient usage of the spark plug.
Within recent years there have been spark plugs designed where there is not a single spark presentation but random spark presentation. Also, it has been known in the past that to have the spark presentation move across the core nose will function to keep the core nose clean and prevent accumulations of oil or carbon and actually will function to remove any accumulations of oil or carbon that may occur on the core nose.